Tractor fifth wheel mounting



March 23, 1948. E. L, MILLER 2,438,323

TRACTOR FIFTH WHEEL MOUNTING Filed lay 10, 1946 l Nv :aN-ron ELMER L. MILLER ','Y @vigi- A'r'ronn tvs Patented Mar. 23, 1948 TRACTOR FIFTH WHEEL MOUNTING Elmer L. Miller, Dayton, Ohio, assignor to The Dayton Steel Foundry Company, Dayton, Ohio,

a corporation of Ohio Application May 10, 1946, Serial No. 668,896

4 Claims. (Cl. 280-33.05)

The present invention relates to mountings for fifth wheels such as commonly used on the tractor of tractor-semi-trailer constructions. 'Ihese devices are wellknown in the trade and consistl of a large at bearing platform or plate which is pivotally mounted on brackets attached to the rear of the tractor. The plate is provided with a rearwardly opening flaring slot designed to receive the king pin on the forward end of the trailer and with suitable jaws by which the kingpin is locked in position when the two vehicles are in coupled relation. The fifth wheel is usually unbalanced so that it rocks downwardly when the vehicles are uncoupled until the rear end thereof rests upon the floor of the tractor, thereby holding the fifth wheel in a tilted position to pass under the forward end of the trailer when the tractor is backed into coupling relation.

Although attempts have lbeen made to improve the mountings for the tractor fth wheel, the standard method is to mount the fifth wheel directly upon transverse pins secured in the. brackets on the body of the tractor. These standard bearings should be lubricated frequently and, as the bearing is a metal-to-metal contact, it is rigid so that the shocks and vibrations from one vehicle are transmitted to the other. The fifth wheel will sometimes remain in horizontal position in spite of its unbalanced condition and does not tilt downwardly when the vehicles are uncoupled. If the driver fails to note and correct this condition accidents may occur when the vehicles are being coupled.

It is one object of the invention to devise a satisfactory mounting for the fifth wheel that will dispense with the necessity of any lubrication at the bearings and will serve as a cushioning medium between the tractor and the trailer and thus absorb much of the relative movement .between the vehicles when in operation. It is a further object of the invention to so mount the fifth wheel on the tractor that the resilient bearing is placed under torsionalstrain when the iifth wheel is horizontal, as when .the vehicles are coupled, so that when the vehicles are uncoupled the torsional effect will insure that the fifth wheel tips downwardly into its proper idle position.

The drawings show a standard or typical fth Wheel mounted in accordance with the principles of the invention, it being understood that the showing is of the preferred or ybest known embodiment of the invention land is not to be taken as limiting it to the details shown and described herein.

Fig. 1 is a view looking from the rear at the fifth wheel in horizontal position, one side being taken onthe vertical sectionindicated by the line I-I of Fig. 2.

Fig. 2 is a side elevation, the normal idle position being shown in full lines and the operative position which the fth wheel assumes in service being shown in dotted lines.

Fig. 3 is a section on the line 3 3 of Fig, 1.

As fifth wheels of various types are standardized, the details thereof will not be described, it being'suiiicient to say that the main body of the fifth wheel is a platform I provided with a V-shaped slot 2 for the reception of the king pin on the trailer and with locking means indicated at the numeral 3 for engaging the king pin to couple the two vehicles together.

The deck of the tractor is shown as a plate 5 and on this plate are the two aligned brackets 6 which are'formed with the vertical lugs 8. Through the lugs of each bracket is passed a stout bearing pin IU which constitutes a support for the fifth wheel. Each pin is non-rotatively mounted with respect to its bracket .by force fitting, or by some other non-rotative connection. A nut l I on the reduced end of the bolt and a lock washer I2 secures the bearing pin in position.

Somewhat forwardly of the transverse center of gravity of the platform I, the body of the platform is provided with a semi-circular formation I4 on either side of which is located the shoulder I5. A semi-circular cap plate i6 is attached to the surfaces I5 by bolts I8 and these two elements at each bearing point constitute a housing which surrounds the pin I 0 but is spaced therefrom to accommodate the bearing which serves the purposes outlined above. f

The .bearing referred to is indicated as a Whole by the numeral i9. It consists of an inner metal sleeve 2G Which is slotted so that when the parts are assembled relative rotation of the pin and the inner sleeve is prevented by the key 2 I. Around i the outside of the bearing is the outer metal sleeve 22, which is force fitted into the surfaces lil-I6 so that there is no rotation of the bearing in .the housing. Between the inner and outer sleeves is a bearing core 25 which is composed. of a relatively hard, tough, but ilexible, rubber composition comparable with a high grade tread stock. It should be capable of withstanding repeated torsional effects without losing its ability to return, when the stresses are relieved, to its normal. unstressed position. The rubber should be heat resistant and of high tensile strength and capable of sustaining the load of the forward end o! the trailer. As the upper surface of the platform forms the load bearing surface for the forwardv end of the trailer, the cushion bearings absorb many of the shocks which would otherwise be transmitted from one vehicle to the other, and therefore both vehicles ride more smoothly than they ride with the old type of mounting.

In making the bearing assembly consisting of the sleeves 26 and 22 and the core 25 the rubber and the sleeves are so joined that there is no creeping between the rubber and the metal surfaces. This may be accomplished in any manner such as known in the art. The surfaces of the metal elements may be roughened or brass plated, or both, and the core may be vulcanized in place, which serves to weld the rubber permanently to the inner and outer sleeves. In lieu of this method parts may be force fitted by inserting a rubber core with a small axial passage in the youter sleeve and then driving the inner sleeve into the passage which compresses, the rubber to such an extent that it is virtually welded to the two surfaces of the members 20 and 22. Othermethods may be employed for forming the bearing assembly; for the purposes of this invention the rubber core and the inner and outer sleeves are united so that any relative rotation of either sleeve with respect to the other will, within the limits to which said movements take place in the fth wheel assembly, be absorbed by the rubber.

When the fth wheel is assembled upon the tractor body the fifth wheel is tilted downwardly either at'the angle which it assumes when the vehicles are uncoupled or a slightly steeper angle. As the bearing sleeves have no relative movement on the pin l or in the housing lli-I6, when the vehicles are coupled and the platform I is moved by the trailer to horizontal position, the torsional stresses which are set up in the rubber core urge the platform toits proper inclined position when the vehicles are uncoupled. The result is that the platform I is unfailingly moved to its proper inclined position.

During the operation of the tractor-trailer combination the rubber core greatly improves the action of the entire assembly because, except in extreme cases, the vibrations and movements of each element of the combination are largely absorbed by the bearing and not transmitted to the other elements of the combination. All necessity for lubricating these parts of the tractor is eliminated.

While a natural rubber is preferred as the basic ingredient of the core 2.5, any acceptable substi- 4 tute may be employed in place thereof and vwhen the term "rubber" is used in the claims it will be understood that such equivalents are comprehended thereby.

What is claimed is:

1. In a fth wheel for tractors the combination of a support, a load bearing platform on thesupport, a pivotal mounting for the platform containing a resilient bushing immovably connected to the support and the platform, said bushing being so mounted that there is tension in the bushing when in horizontal position, said tension being relaxed when the platformis tilted downwardly.

2. In a fth wheel for tractors the combination of a support on the tractor, a bearing pin on the support, a platform, a housing on the platform, means to arrest the platform in a tilted position,l and a resilient bushing between the pin and the housing, said bushing being under torsional stress whereby it tends to move the platform to the inclined position.

3. In a fth wheel for tractors, the combination of a support on the tractor, a bearing pin on the support, a platform, a housing on the platform, means to arrest the platform in a tilted position, and a rubber bushing between the pin and the housing, said bushing being so mounted that it is torsionally deformed when theplatform is in horizontal position and tends to move the platform toits tilted position.

4. In a fth wheel for tractors, the combination of a bracket on the tractor, a pin immovably mounted in the bracket, a pivoted platform, a housing on the platform surrounding b ul spaced from the pin, and a rubber bushing'assembly between the pin and the housing, said bushing comprising inner and outer shells fixed to the pin and housing, respectively, and a, rubber core between the shells and immovably united therewith, said bushing assembly being so constructed and arranged that the rubber of the core is under torsional stresses when the platform is in horizontal position.

Y ELMER L. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,263,114 Winn Nov. 18, 1941 2,353,267 Reid July 11, 1944 2,359,499 Walther Oct. 3, 1944 

